1. Field of the Invention
The invention relates to a support device for the cultivation of Macro organisms in marine waters with at least one ring structure disposed below the surface of the water between at least one buoyancy device and an anchoring device and provided, within a closed outer ring, with a cobwebby cultivation unit of radial support lines and azimuthal cultivation lines.
2. The Prior Art
Primary among the Macro organisms which can be cultivated in marine waters, such as the seas and oceans, are the algae (macro algae such as brown, green and red algae) and mussels (such as blue mussels and oysters). In east Asia the cultivation of algae has a long tradition, with the requisite experience extending back several centuries. However, it is depending upon using such areas of the sea which are substantially and well protected from rough weather and marine conditions, such as bays or estuaries. Long lines, rafts or pole systems constitute the major support devices for algae cultures. They are anchored at the bottom and are quite prone to suffer from rough seas. Areas of the sea subject to harsh weather conditions have heretofore scarcely been used for the marine cultivation of any potentially useful marine organisms. Only a few years ago marine cultivation, because of conflicts in coastal regions between users and consequential complicated legal conditions, urban waste water as well as better oxygen conditions, began to extend to the offshore regions of the oceans. In Germany, submersible cages for the cultivation of salt water fish in the offshore region were developed as early as the 1970s, and further developments were later used in Canada and the USA. Such systems are still in the pilot stages. However, the primary purposes of cultivating macro algae in regions of unfavorable weather conditions were for research. Mention is here to be made of a project of the Isle of Man where different structures, especially long-line techniques, were utilized. Further more, from the Japanese abstract of JP 2001054330 A there is known a dive cage structure for algae cultivation in the sea at depths of 10 m to 25 m and in which a plurality of braces and ropes is disposed as a cultivation unit between floodable containers at the corners of the structure. Lowering and hoisting of the structure takes place by evacuating and flooding the corner containers and by direct engagement of the unstable cultivation unit. A pole-like sticking structure with algae cultures imbedded in an eyelet is known from Japanese abstract JP 11196696 A which is stuck into the bed of the sea. Furthermore, from WO 86/02395 it is known to attach the lower end of laminar algae cultures to a stake in the sea bed by a multiple rope arrangement. However, this structure can only be used near the coast and is unsuitable for use in heavy seas.
In Germany, too, tests were conducted during the years between 1994 and 1996 to cultivate macro algae neat Heligoland under North Sea conditions. This was a project “Mass culture of marine macro algae near Heligoland for producing phyco-colloids and for use as biosorption means” by Luening and Buchholz sponsored by the (German) Federal Ministry of Education and Research (see Final Report relating to project 03F0096A, 1996, Part 1). For the experiments, different support devices of long-line, ladder and lattice structured were developed for cultivating the macro algae Laminaria saccharina and Laminaria digitata. However, none of these structures were capable of withstanding the oceanographic conditions near Heligoland. This was the first time that attempts were made to build, and to use at different sites, an ring structure for the cultivation of laminaria species. However, under the pressure of the strong and permanent currents a large number of these rings were destroyed. Other rings which resisted the effects displayed partially atrophied growth. Attempts to build a support device of ring structure in the more protected harbor entrance in order to avoid the force of waves and currents initially resulted in successful longitudinal growth of the algae. However, they quickly atrophies since because of the low current various parasites, animals and other algae settled on the leaves so that they broke off which even led to negative rates of growth. It became apparent that the algae which in nature can only be found at exposed sites required exposure to certain currents.
The support devices known from the Final Report (see its pages 6 to 9 and FIGS. 12 to 16 and 18) are the ones of various ring structures. Among others, tests were made with an ring structure disposed below the water surface and made of a single PE plastic tube as the external ring of a diameter of 5 m. The external ring was provided with 80 m of cultivation line in a cobwebby arrangement. The cultivation line serves to grow the Macro organisms which may either be caught from the sea (e.g. mussel larvae) or be imbedded into the cultivation line as culture seed (e.g. algae seed). Buoyancy was ensured by eight fenders (23 kg each) as buoyancy means which were evenly distributed on the external ring and which also served as markers. They were found to suffer from the disadvantage of the radially arranged fenders, contrary to assumptions, being incapable of maintaining the ring structure in a horizontal position even at strong currents. Individual fenders could not support the ring structure in strong currents and were pushed below the surface of the water. This subjected the fenders increasingly to compression and relief and to their partial destruction. The anchoring system was conceived such that the entire ring structure had to be disassembled for harvesting. To this end one of the eight fenders of the ring structure had to be engaged and hoisted from a ship. This caused the external ring to be rotated to an orientation vertically of the water surface which when the external ring touched the hull of the ship often resulted in the loss of the algae. Recovering the ring structure by way of several roped connected to the circumference also proved to be disadvantageous since it caused strong deformations of the algae growth covered ring structure. In most cases it was necessary to release the ring structure in order to tow into the protected harbor for harvesting. Moreover, the fenders could become entangle with each other and thus cause the free ropes to become damaged by abrasion.
A first possible yet theoretical further development of the described support device of ring structure may be taken from the AWI Publication “Beispiele aus unserer Forschung 2002” (Examples from our Research 2002), pages 33 to 39 under the title “Kombinierte Windpark- und Marikulturnutzung in der Nordsee” (Combined Wind Park and Marine Culture Use in the North Sea) by B. H. Buck which was based on a previously executed feasibility study (Berichte zur Polar- und Meeresforschung [Reports on Polar and Ocean Research] Apr. 12, 2002, Chapter 6, pages 74-85.The rings and long lines disclosed by the AWI publication constitute possibilities of cultivation and are mere theory. At present, no wind parks are existing. The schematic presentation in accordance with FIG. 9b discloses an arrangement of a support device with an ring structure in an offshore region in which the support device is maintained stationary 1.5 m to 5 m below the surface of the sea between the pylon of a wind energy plant and an anchoring arrangement made up of an anchor chain and an anchor stone. In that arrangement, the two arresting points are affixed to the outermost points on the external ring of the ring structure. An arrangement of two anchoring points with brackets at the external ring (FIG. 9b) is as possible as is an aggregate of several ring structures around the pylon (FIG. 9a). Again, the closed external ring is provided with a cobwebby cultivation unit consisting of radial support lines and azimuthal cultivation lines, the hub being formed by a common knob.
By the last-described support devices with ring structures of one or more external rings being the closest prior art from which the present application is proceeding, the possibility is to be provided, particularly in offshore regions, of cultivating Macro organisms in protected and unprotected regions of the sea where medium to strong currents as well as periods of high waves prevail, or may temporarily occur. In Europe, protected and substantially unprotected regions exist in all areas of the exclusive economic zone and at almost all locations of the coastal sea. Since the coastal sea for reasons of user conflicts and nature preservation can hardly be used at all, the indications of aqua culture are that more and more exposed and substantially open (unprotected) areas of the sea will gradually be used.